1. Field of the Invention
This invention relates to an electrical connector having cavities receiving terminals each of which has one end connected to a lead, and more particularly to such a connector employing a retainer providing double engagement for the terminals received in the cavities so that the terminals can be held in position therein.
2. Description of the Prior Art
FIGS. 7 and 8 illustrate a conventional electrical connector employing a retainer providing double engagement for the terminals. FIGS. 9 and 10 illustrate another conventional connector employing such a retainer. Referring to FIGS. 7 and 8, the connector comprises a housing 1 with cylindrical cavities 1a receiving respective terminals 2. Each cavity 1a has an open rear end through which the terminal 2 is inserted. A cap-shaped retainer 3 is fitted on an outer periphery of the rear end of the housing 1. The retainer 3 has terminal insertion apertures 3a corresponding to the respective rear openings of the cavities 1a. A protrusion 3b is formed on the upper inner periphery of the retainer 3 so that it protrudes toward the interior of the enters into the corresponding cavity 1a to collide with the rear end of the terminal 2. The state of the housing 1 and the retainer 3 as shown in FIG. 8 will be referred to as "full engagement".
The retainer 3 can be engaged with the housing 1 before the full engagement state, assuming a position away from its position in the full engagement state, as shown in FIG. 7. In this position away from that in the full engagement state, each protrusion 3b is out of the corresponding cavity 1a. The state of the housing 1 and the retainer 3 as shown in FIG. 7 will be referred to as "preliminary engagement".
When assembling the above-described connector, the terminals 2 are inserted into the cavities 1a from the terminal insertion apertures 3a, respectively, with the housing 1 and the retainer 3 in the state of preliminary engagement. After being forced down in the direction of arrow A from the preliminary engagement state shown in FIG. 7, the retainer 3 is thrust in the direction of arrow B in FIG. 8. Thus, a two-stage operation is necessitated in order that the retainer 3 is engaged with the housing 1 in the full engagement state, that is, pushing the retainer 3 in the direction of arrow A and thrusting it in the direction of arrow B. The two-stage operation requires an operator to be well-skilled, resulting in a problem in working efficiency. Furthermore, the two-stage operation prevents automatization of the terminal inserting work.
On the other hand, the connector shown in FIGS. 9 and 10 comprises a housing 4 with cylindrical cavities 4a receiving terminals 5, respectively. A space or retainer receiving portion 4b is defined in an upper rear portion of the housing for receiving a retainer 6. The retainer 6 has at its distal end a flexible arm 6a and is inserted into the retainer receiving portion 4b as led by the arm 6a. The retainer 6 has a rear end which is engageable at its top face with an upper face of the retainer receiving portion 4b. The retainer 6 is engaged with the retainer receiving portion 4b both when it assumes a preliminary engagement position in which the base is not completely received in the retainer receiving portion 4a, as shown in FIG. 9, and when it assumes a full engagement position in which it is completely received in the retainer receiving portion 4b.
The retaining receiving portion 4b has an inclined face 4c at its front end. The distal end of the arm 6a is positioned rearwardly of the open end of the housing relative to the inclined face 4c when the retainer 6 is at the preliminary engagement position. When the retainer 6 is moved from the preliminary engagement position to the full engagement position, the distal end of the arm 6a is flexed downwardly along the inclined face 4c so that the arm 6a advances downwardly into the cavity 4a.
To assemble the above-described connector, the retainer 6 is inserted into the retainer receiving portion 4b as led by the arm portion 6a such that the retainer 6 is engaged with the housing at the preliminary engagement position. Then, the terminals 5 are inserted into the respective cavities 4a and the retainer 6 is thrust in the direction of arrow C in FIG. 10 such that it is moved from the preliminary engagement position to the full engagement position. The arm 6a of the retainer 6 then collides with the inclined faces 4c to be flexed downwardly. The arm 6a then collides with a portion of the terminal 5 defining the bottom of a recess 5a to push the same deep into the cavity 4a, thereby holding the terminals 5 in the respective cavities 4a.
The number of the arms 6a to be flexed corresponds to the number of the terminals received in the respective cavities 4a. Accordingly, a large operating force is necessary when there are a large number of terminals 5 and results in reduction in the working efficiency. Furthermore, the arm 6a loses its resiliency when the retainer 6 is returned to the preliminary engagement position during an inspection of the connector. In this case, the arm 6a remains bent downwardly and accordingly, the terminal 5 cannot be pulled out.